This invention relates to flushing cisterns.
A conventional flushing cistern comprises a tank to which water is fed through a float controlled inlet valve with a discharge valve which is actuated externally. The level of water in the cistern is controlled by the float. Theoretically only the volume defined by that level is discharged during flushing. However, in practice as soon as the float drops, the inlet valve opens and water flows from the inlet through the outlet until the outlet valve has passed through its closure cycle. At high water pressures the extra discharge could be considerable and is often wasteful.
It has already been proposed that a cistern be provided with an auxiliary float chamber with communication between the main body of the cistern and the auxiliary chamber taking place via a syphonic tube. The result is that the inlet valve remains closed until there is discharge from the auxiliary float chamber through the syphonic tube. As the latter discharge is arranged to be quick, the flow of inlet water during the period of the outlet is open, is minimised to a large extent. Backflow was intended to be through the syphonic tube, but this was seldom effective.
The auxiliary float chamber as previously proposed is difficult to manufacture and install. An object of the invention is to provide an auxiliary float chamber which will be easy to make and install.